export default {
  // 为当前模块开启命名空间
  namespaced: true,
  
  // 模块的 state 数据
  state: () => ({
      // 购物车的数组，用来存储购物车中每个商品的信息对象
      cart: JSON.parse(uni.getStorageSync('cart') || '[]'),
    }),
  // 模块的 mutations 方法 ： 子模块状态更改函数
  mutations: {
    addToCart(state, goods) {
      const findResult = state.cart.find(x => x.goods_id == goods.goods_id)
      if (!findResult) {
        state.cart.push(goods)
      } else {
        findResult.goods_count++
      }
      this.commit('m_cart/saveToStorage')
    },
    saveToStorage(state) {
      uni.setStorageSync('cart', JSON.stringify(state.cart))
    },
    //更新本地购物车商品的勾选状态
    updateGoodsState(state, goods) {
      const findResult = state.cart.find(x => x.goods_id == goods.goods_id)
      if (findResult) {
        findResult.goods_state = goods.goods_state
        this.commit('m_cart/saveToStorage')
      }
    },
    //更新本地购物车所有商品的勾选状态
    updateAllGoodsState(state, newState) {
      state.cart.forEach(x => x.goods_state = newState)
      this.commit('m_cart/saveToStorage')
    },
    //更新本地购物车商品的勾选状态
    updateGoodsCount(state, goods) {
      const findResult = state.cart.find(x => x.goods_id == goods.goods_id)
      if (findResult) {
        findResult.goods_count = goods.goods_count
        this.commit('m_cart/saveToStorage')
      }
    },
    //删除购物车商品
    removeGoodsById(state, goods) {
      state.cart = state.cart.filter(x => x.goods_id != goods.goods_id)
      this.commit('m_cart/saveToStorage')
    }
  },
  actions: { // 子模块异步操作
  },
  
  getters: {// 模块的 getters 属性-子模块计算属性
  //购物车中所有商品总数量
    total(state) {
      // let c = 0
      // state.cart.forEach(x => c += x.goods_count)
      // return c
      return state.cart.reduce((total, item) => total += item.goods_count, 0)
    },
    //勾选商品总数量 
    checkedCount(state) {
      return state.cart.filter(x => x.goods_state).reduce((total, item) => total += item.goods_count, 0)
    },
    checkedGoodsAmount(state) {
      return state.cart.filter(x => x.goods_state)
                        .reduce((amount, item) => amount += item.goods_price * item.goods_count ,0).toFixed(2)
    }
  }
}